Any problems/changes: Used two layers of craft foam for the brim. Folded the brim in half and sewed half together then used as a template to cut foam. Sewed the ends into the brim so I didn’t have to sew them in.
To sew to hat, turned hat inside out and matched the seam on the brim to the hat edge then sewed on.
Sewed the strap on whilst sewing on the buttons.